body {
    margin: 0;
    overflow: hidden;
    background: linear-gradient(to bottom, #001f3f 0%, #000 100%);
    animation: thunder 15s infinite;
}

@keyframes thunder {
    0%, 100% {
        background-color: #001f3f;
    }
    2%, 4%, 6% {
        background-color: #fff;
    }
    3%, 5%, 7% {
        background-color: #001f3f;
    }
    10% {
        background-color: #fff;
    }
    11% {
        background-color: #001f3f;
    }
    50% {
        background-color: #001f3f;
    }
}

.container {
    position: relative;
    z-index: 1;
}

/* 添加闪电效果 */
.lightning {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: transparent;
    pointer-events: none;
    overflow: hidden;
}

.lightning::before,
.lightning::after {
    content: '';
    position: absolute;
    width: 2px;
    height: 0;
    background: linear-gradient(to bottom, rgba(255,255,255,0.8), rgba(255,255,255,0));
    animation: lightning 15s infinite;
}

.lightning::before {
    left: 20%;
    animation-delay: 5s;
}

.lightning::after {
    left: 60%;
    animation-delay: 10s;
}

@keyframes lightning {
    0% {
        height: 0;
        opacity: 0;
    }
    1% {
        height: 100%;
        opacity: 1;
    }
    2% {
        height: 0;
        opacity: 0;
    }
    100% {
        height: 0;
        opacity: 0;
    }
}